Improvement in centering devices



W. D. SLACK.

Centering. Devices.

Patented Nov. 17, 1874.

mviutoh 8 ITNESSES /%w/ ATTORNEYS.

- THE GRAPHIC co. rnTo-Ll'maaa. 41 PARK PLACE, NIY.

UNITED STATES PATENT OFFICE.

WILLIAM D. SLACK, OF LEWISBURG, PENNSYLVANIA.

IMPROVEMENT IN CENTERING DEVICES.

Specification forming part of Letters Patent No. 157,030, dated November 17, 1874 application filed May 16, 1874.

To all whom it may concern:

Be it known that I, WILLIAM D. SLACK, of Lewisburg, in the county of Union and State of Pennsylvania,have invented a new and Improved (Jentering Device; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawing forming a part of this specification, in which Figure 1 is a sectional elevation; Fig. 2, reverse plan view; Fig. 3, plan view.

This invention relates to that class of tools known as centering-machines; and its object is to enable mechanics rapidly and easily to find the'center of hubs, shafts, and other similar configurations of wood or metal.

It consists of a plate, A, revolving in the end of a cup, B, having handle K, said plate having alip or ledge on its upper surface, that keeps it in its place. To the inside of the top of the cup B are pivoted, at equal distances from the center, the fingers 0, all being of the same length, and to these fingers are pivoted, at the same distances from their extremities, linksD of the same length, said links being in turn pivoted to the bottom of revolving plate A, each at the same distance from the center of the plate, and equidistant apart. The top of plate A terminates in a hub, E, through which, extending through the bottom of the said plate, is ahole, in which plays the centeringpunch F, which is inclosed in a spiral spring, G, the said punch being provided at its upper end with a knob, H, for the hand or hammer. To the hub E is pivoted, in a horizontal position, a forked lever, I, by means of which the plate A and appurtenances are made to revolve, said lever having a ratchet-toothed flange, a, for the ratchets b, and a spiral spring, 0, to keep it in place.

To operate this machine, open the fingers O by revolving the plate by means of the lever I; then place the shaft to becentered between the fingers and move the lever in the opposite direction until they clamp the shaft; and now, as the center of the shaft is immediately below the punch F, a sudden tap with the hand or hammer upon the knob of the punch F will lea e a puncture in the right place.

Having thus described my invention, what I claim as new, and desire to protect by Letters Patent, is

The rotatable plate A, lever I, and tooth a, rod F, with knob and steel point, and spiral springs G c, in combination with the cup B, ratchets b, fingers O, and links D, as and for the purpose specified.

WILLIAM D. SLACK.

Witnesses:

A. E. BOWER, LOVING K. JONES. 

